The head of an inquiry into historic sex abuse by politicians and other powerful figures has said she will not quit, despite her brother being linked to an Establishment cover-up of the same paedophile ring she will be investigating. Baroness Butler-Sloss, a retired judge, refused to bow to demands for her resignation less than 24 hours after her appointment.

The Daily Mailreports that politicians and legal experts said it would be inappropriate for her to accept the post since her late brother, Sir Michael Havers, was Attorney General in Margaret Thatcher’s government, when many of the allegations were made.

Geoffrey Dickens, the MP who reported many of the claims in the 1980s, accused Sir Michael of a ‘whitewash’ and ‘the cover-up of the century’ when he took no action on the claims.

Actor Nigel Havers, son of Sir Michael, yesterday defended his aunt. He said she “had no political ties to my father and knew nothing about what was going on in the House of Commons at that time.”

“She has every right to lead the inquiry,” he added.

Labour MP Simon Danczuk, who has campaigned against child abuse, was not convinced, however. He said: “It’s astonishing the Government didn’t realise they were appointing the sister of someone who had tried to deter the prosecution of a significant paedophile. It’s far too Establishment – and the Government need to think again.”

It was also reported last night that Baroness Butler-Sloss made significant errors in an inquiry into child abuse within the Church of England three years ago. She had to issue a six-page appendum in which she apologised for “inaccuracies” in her report eight months after it had been published.

Lady Butler-Sloss remained defiant yesterday, however, saying: “If people think I am not suitable then that’s up to them.”

A spokesman for Downing Street also said: “She commands the very highest of respect for her professional expertise and integrity.”